Display system and vehicle including the same, and method of showing state of secondary battery

ABSTRACT

In representation processing, when a capacity retention is higher than a threshold value while a warranty condition is satisfied, an ECU has the capacity retention shown in a first manner. When the capacity retention is equal to or lower than the threshold value while the warranty condition is satisfied, the ECU has the capacity retention shown in a second manner.

This nonprovisional application is based on Japanese Patent ApplicationNo. 2019-158627 filed with the Japan Patent Office on Aug. 30, 2019, theentire contents of which are hereby incorporated by reference.

BACKGROUND Field

The present disclosure relates to a display system and a vehicleincluding the same, and a method of showing a state of a secondarybattery.

Description of the Background Art

A secondary battery as a motive power source has been mounted on a largenumber of recent electric appliances. The secondary battery has beenknown to deteriorate and become lower in full charge capacity as it isused and time elapses. When the full charge capacity becomes low, anelectric appliance may be shorter in maximum continuous drive time,which may be great inconvenience to a user. Therefore, the full chargecapacity is an important indicator for the user.

For example, in an electrically powered vehicle such as an electricvehicle including a secondary battery as a motive power source, withlowering in full charge capacity, a distance which the electricallypowered vehicle can travel with electric power stored in the secondarybattery (what is called an EV driving range) decreases. In order toeliminate user's anxieties, the full charge capacity may be shown. Forexample, Japanese Patent Laying-Open No. 2011-257213 discloses a displaysystem that shows both of a state of charge (SOC) and a full chargecapacity of a secondary battery.

SUMMARY

Some electrically powered vehicles are covered by a warranty from amanufacturer, of replacement of a secondary battery or processing forrefreshing the secondary battery when deterioration of the secondarybattery progresses and the full charge capacity is equal to or lowerthan a threshold value. A user of the electrically powered vehiclecovered by the warranty can receive a warranty service for the secondarybattery through a dealer or the like when the full charge capacity isequal to or lower than a threshold value.

In a general electric appliance including a secondary battery as amotive power source (for example, a smartphone familiar to a largenumber of users), an SOC as an indicator that indicates remaining power(remaining capacity) of the secondary battery is always shown. On theother hand, the full charge capacity is not always shown in manyelectric appliances. Therefore, a large number of users are not familiarwith the full charge capacity. Accordingly, even though both of the SOCand the full charge capacity are shown on a display screen of anelectrically powered vehicle as in the display system disclosed, forexample, in Japanese Patent Laying-Open No. 2011-257213, a user may notbe able to intuitively recognize in which condition of the shown fullcharge capacity the battery is eligible for receiving a warrantyservice.

The present disclosure was made to solve the problems above, and anobject thereof is to allow a user to readily intuitively recognizeeligibility for receiving a warranty service for a secondary battery.

(1) A display system according to the present disclosure includes adisplay apparatus that shows a first indicator relating to a full chargecapacity of a secondary battery and a controller that controls thedisplay apparatus. The controller controls the display apparatus tonotify, when a full charge capacity of the secondary battery is equal toor lower than a threshold value, that the full charge capacity of thesecondary battery is equal to or lower than the threshold value.

According to the above configuration, when the full charge capacity ofthe secondary battery is equal to or lower than the threshold value, anotification that the full charge capacity of the secondary battery isequal to or lower than the threshold value is given. In other words,when the secondary battery is now eligible for receiving a warrantyservice, a notification that the secondary battery is eligible forreceiving the warranty service is given. A user can thus intuitivelyrecognize eligibility for receiving a warranty service for the secondarybattery.

(2) In one embodiment, the controller controls the display apparatus tonotify that the full charge capacity of the secondary battery is equalto or lower than the threshold value by varying a manner ofrepresentation of the first indicator.

According to the above configuration, when the secondary battery is noweligible for receiving the warranty service, a manner of representationof the first indicator is varied. With variation in manner ofrepresentation of the first indicator, the user can intuitivelyrecognize eligibility for receiving the warranty service for thesecondary battery.

(3) In one embodiment, the controller controls the display apparatus tonotify that the full charge capacity of the secondary battery is equalto or lower than the threshold value by showing a warning.

According to the configuration, when the secondary battery is noweligible for receiving the warranty service, a warning is shown. Withrepresentation of the warning, the user can intuitively recognizeeligibility for receiving the warranty service for the secondarybattery.

(4) In one embodiment, the controller controls the display apparatus tonotify, when an estimation error of the full charge capacity of thesecondary battery exceeds a reference value, that accuracy of the firstindicator is low.

Environments where the full charge capacity of the secondary battery isestimated are various, and the full charge capacity of the secondarybattery is not necessarily estimated in a stable environment. Therefore,there are various factors that may vary an estimated value of the fullcharge capacity. When an estimation error of the full charge capacity islarge, the first indicator shown at each estimation timing may greatlybe varied, which may make a user feel strange. According to the aboveconfiguration, when the estimation error of the full charge capacityexceeds the reference value, a notification about low accuracy of thefirst indicator is given. The user can thus recognize low accuracy ofthe first, indicator. Therefore, even though the first indicator shownat each estimation timing is greatly varied, strange feeling felt by theuser can be lessened as compared with an example where the user is notaware of low accuracy of the first indicator.

(5) In one embodiment, the display apparatus shows a capacity retentionin segment representation as the first indicator, the capacity retentionrepresenting a ratio of a current full charge capacity to an initialfull charge capacity of the secondary battery. The controller controlsthe display apparatus to turn on segments corresponding in number to thecapacity retention. The controller controls the display apparatus tovary a color of at least one of the segments when the full chargecapacity of the secondary battery is equal to or lower than thethreshold value.

According to the above configuration, when the full charge capacity ofthe secondary battery is equal to or lower than the threshold value, acolor of a segment is varied. The user can thus intuitively recognizeeligibility for receiving the warranty service for the secondarybattery.

(6) In one embodiment, the controller controls the display apparatus tonotify that the full charge capacity of the secondary battery is equalto or lower than the threshold value when a warranty condition issatisfied, and controls the display apparatus not to notify that thefull charge capacity of the secondary battery is equal to or lower thanthe threshold value when the warranty condition is not satisfied.

(7) In one embodiment, the warranty condition is satisfied when aprescribed period has not elapsed since start of use of the secondarybattery.

(8) In one embodiment, the warranty condition is satisfied when a traveldistance of a vehicle incorporating the secondary battery is shorterthan a prescribed distance.

(9) In one embodiment, the warranty condition is satisfied when aprescribed period has not elapsed since start of use of the secondarybattery and when a travel distance of a vehicle incorporating thesecondary battery is shorter than a prescribed distance.

The warranty service for the secondary battery may be conditioned onfulfillment of a warranty condition. In such a case, when a notificationthat the full charge capacity of the secondary battery is equal to orlower than the threshold value is given even though the warrantycondition is not satisfied, the user may erroneously recognizeeligibility for receiving the warranty service or may feel bothered bythe notification given in spite of ineligibility for receiving thewarranty service. According to the configuration in (6) to (9), when thewarranty condition is satisfied, a notification that the full chargecapacity of the secondary battery is equal to or lower than thethreshold value is given. When the warranty condition is not satisfied,however, the notification is not given. Since the notification is thusnot given when the secondary battery is not eligible for receiving thewarranty service, erroneous recognition by the user caused by thenotification or the user being bothered by the notification can besuppressed.

(10) In one embodiment, the controller controls the display apparatus tonotify, when a warranty condition is not satisfied, that the warrantycondition is not satisfied.

According to the above configuration, the user can recognize that thewarranty condition is not satisfied and the secondary battery is noteligible for receiving the warranty service.

(11) In one embodiment, the controller controls the display apparatus toshow a second indicator indicating a warranty condition.

For example, a prescribed period and/or a prescribed distance thatrepresent(s) a warranty condition can be shown as the second indicator.Instead of the prescribed period, remaining days or a date on which aprescribed period expires may be shown as the second indicator.Furthermore, instead of the prescribed distance, a distance that remainsuntil the prescribed distance may be shown as the second indicator. Byshowing the second indicator, for example, expiration of a prescribedperiod or excess over a prescribed distance in spite of the fact thatthe secondary battery is eligible for receiving the warranty service canbe suppressed.

(12) A vehicle according to another aspect of the present disclosureincludes a secondary battery and the display system described in any of(1) to (11).

According to the above configuration, representation that allows a userto intuitively recognize eligibility for receiving the warranty servicefor the secondary battery can be realized in a vehicle.

(13) In a method of showing, a state of a secondary battery according toyet another aspect of the present disclosure, a first indicator relatingto a full charge capacity of the secondary battery is shown. The methodof showing a state of a secondary battery includes obtaining a fullcharge capacity of the secondary battery and notifying, when the fullcharge capacity of the secondary battery is equal to or lower than athreshold value, that the full charge capacity of the secondary batteryis equal to or lower than the threshold value.

The foregoing and other objects, features, aspects and advantages of thepresent disclosure will become more apparent from the following detaileddescription of the present disclosure when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing an overall configuration of asystem including a vehicle according to an embodiment.

FIG. 2 is a diagram for illustrating an instrument panel.

FIG. 3 is a diagram (No. 1) showing an example where a capacityretention is shown on a multi-information display.

FIG. 4 is a diagram (No. 2) showing an example where a capacityretention is shown on the multi-information display.

FIG. 5 is a flowchart showing calculation processing in the embodiment.

FIG. 6 is a diagram for illustrating an exemplary method of calculatingan estimation error of a capacity of a battery.

FIG. 7 is a conceptual diagram showing a map for calculating anestimation error of a capacity of the battery.

FIG. 8 is a diagram for illustrating a method of calculating a capacityretention and an estimation error of a capacity of the battery.

FIG. 9 is a flowchart showing representation processing in theembodiment.

FIG. 10 is a diagram showing an example where a capacity retention isshown on the multi-information display in a first modification.

FIG. 11 is a diagram showing an example where a capacity retention isshown on the multi-information display in a second modification.

FIG. 12 is a diagram showing an example where a capacity retention isshown on the multi-information display in a third modification.

FIG. 13 is a diagram showing an example where a capacity retention and awarranty condition are shown on the multi-information display.

FIG. 14 is a diagram showing an example where a capacity retention isshown on the multi-information display in another manner.

FIG. 15 is a diagram showing another example where a capacity retentionis shown on the multi-information display in another manner.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present disclosure will be described below indetail with reference to the drawings. The same or correspondingelements in the drawings have the same reference characters allotted anddescription thereof will not be repeated.

Overall Configuration

FIG. 1 is a diagram schematically showing an overall configuration of asystem including a vehicle according to the present embodiment. Avehicle 1 according to the present embodiment is an externallychargeable electric vehicle in which a vehicle-mounted secondary batteryis charged with electric power supplied from a power supply outside thevehicle (which is also referred to as an “external power supply” below).Vehicle 1 should only incorporate a secondary battery as a motive powersource. and is not limited to an electric vehicle. Vehicle 1 may be, forexample, a plug-in hybrid vehicle, a hybrid vehicle, or a fuel cellvehicle.

Referring to FIG. 1, vehicle 1 includes a motor generator 10, atransmission gear 22, a drive wheel 23, a power control unit (PCU) 30, asystem main relay (SMR) 41, a battery 50, an instrument panel 70, a carnavigation system (car navigator) 80, a communication apparatus 90, andan electronic control unit (ECU) 100. Vehicle 1 includes a charge relay42, a charger 61, and an inlet 62 as components for external charging.

Motor generator (three-phase alternating-current (AC) motor) 10generates kinetic energy for running vehicle 1 by receiving AC powerfrom PCU 30. Kinetic energy generated by motor generator 10 istransmitted to drive wheel 23. On the other hand, motor generator 10converts kinetic energy of vehicle 1 into electric energy when vehicle 1is decelerated or stopped. AC power generated by motor generator 10 isconverted to direct-current (DC) power by PCU 30 and supplied to battery50. Regenerative power can thus be stored in battery 50. Motor generator10 is thus configured to generate driving force or braking force ofvehicle 1 by transmitting and receiving electric power to and frombattery 50 (that is charging and discharging of battery 50).

When vehicle 1 is configured as a hybrid vehicle which furtherincorporates an engine (not shown) as a motive power source, output fromthe engine in addition to output from motor generator 10 can be used asdriving force for travel. Alternatively, an additional motor generator(not shown) which generates power based on output from the engine canalso further be incorporated to generate charging power for battery 50based on output from the engine.

PCU 30 converts DC power stored in battery 50 into AC power and suppliesAC power to motor generator 10 in response to a control signal from ECU100. PCU 30 converts AC power generated by motor generator 10 to DCpower and supplies DC power to battery 50.

SMR 41 is electrically connected to a power line that connects PCU 30and battery 50 to each other. SMR 41 switches between supply and cut-offof electric power between PCU 30 and battery 50 in response to a controlsignal from ECU 100.

Battery 50 is a DC power supply that is chargeable and dischargeable. Asecondary battery such as a lithium ion secondary battery or a nickelmetal hydride battery can be employed as battery 50. Battery 50 supplieselectric power for generating driving force of vehicle 1 to PCU 30.Battery 50 stores electric power generated by motor generator 10.

Battery 50 includes a monitoring unit 51 that monitors a state ofbattery 50. Monitoring unit 51 includes a voltage sensor that detects avoltage VB of battery 50, a current sensor that detects a current IBinput to and output from battery 50, and a temperature sensor thatdetects a temperature TB of battery 50 (none of which is shown). Eachsensor outputs a signal indicating a result of detection to ECU 100. ECU100 can calculate an SOC of battery 50 and/or calculate a full chargecapacity of battery 50 based on a result of detection received frommonitoring unit 51.

Charge relay 42 is electrically connected to a power line that connectsbattery 50 and charger 61 to each other. Charge relay 42 switchesbetween supply and cut-off of electric power between battery 50 andcharger 61 in response to a control signal from ECU 100.

Charger 61 includes, for example, an AC/DC converter (not shown).Charger 61 converts AC power supplied from an external power supply 3through a charging cable 2 to DC power and outputs DC power to battery50.

Instrument panel 70 shows various states of vehicle 1 under the controlby ECU 100. FIG. 2 is a diagram for illustrating instrument panel 70.Referring to FIG. 2, instrument panel 70 includes a speed displaysection 71 where a speed of vehicle 1 is shown, a trip display section72 where a travel distance of vehicle 1 is shown, and a remainingcapacity display section 73 where an SOC as an indicator that indicatesremaining power (remaining capacity) of the battery is shown. In FIG. 2,100 km/h is shown in speed display section 71 by way of example. In FIG.2, 20 km is shown in trip display section 72 by way of example. In FIG.2, an SOC of 100% is shown in remaining capacity display section 73 byway of example. The SOC represents a current amount of stored power tothe full charge capacity of battery 50 in percentage.

Instrument panel 70 includes a multi-information display 74 and awarranty lamp 75, and a user can select contents to be shown in themulti-information display. The user can have multi-information display74 selectively show, for example, a full charge capacity (a capacityretention in an example which will be described later) of battery 50, adriving range, an average vehicle speed, and a state ofregeneration/power running of battery 50.

FIG. 3 is a diagram showing an example where a capacity retention Q isshown on multi-information display 74. Capacity retention Q represents aratio [unit of %] of a current full charge capacity C of battery 50 to afull charge capacity C0 in an initial state of battery 50 and it iscalculated in an expression (1) below. In the present embodiment,capacity retention Q is shown as an indicator (a first indicator)relating to the full charge capacity of battery 50. Multi-informationdisplay 74 may show current full charge capacity C instead of capacityretention Q. In this case, multi-information display 74 shows, forexample, current full charge capacity C and full charge capacity C0 inthe initial state of battery 50.

Q=C/C0×100  (1)

A full charge capacity measured at the time of manufacturing of battery50 (or vehicle 1) or a specification value (a catalog value) of the fullcharge capacity of battery 50 may be employed as initial value C0 of thefull charge capacity.

Referring to FIG. 3, for showing capacity retention Q, multi-informationdisplay 74 includes a first display section 76, a second display section77, and a third display section 78.

First display section 76 provides segment representation of capacityretention Q. In first display section 76, capacity retention Q is shownwith ten segments 760 to 769 that constitute a scale. Specifically, onesegment represents 10% capacity retention Q. On and off of each ofsegments 760 to 769 (virtual on and off based on an image in the presentembodiment) is controlled in accordance with a control signal from ECU100. With lowering in capacity retention Q, segments 760 to 769 areturned off sequentially from a side of segment 769. For example, whencapacity retention Q of battery 50 lowers by a unit quantity (10%) fromthe state that all of segments 760 to 769 are on (capacity retention of100%), segment 769 is turned off. FIG. 3 shows an example where capacityretention Q is 80%. Therefore, segments 768 and 769 are turned off andsegments 760 to 767 are turned on. In first display section 76, thenumber of segments is not limited to ten but any number of segments notsmaller than two may be set. For example, ten or more segments may beprovided.

Second display section 77 shows capacity retention Q with a numericvalue (80% in FIG. 3). A unit quantity of capacity retention Q shown insecond display section 77 may be smaller (for example, 1%) than a unitquantity of capacity retention Q shown in first display section 76.

Third display section 78 shows an accuracy lamp for giving anotification about low accuracy in estimation of capacity retention Q.The accuracy lamp is turned on and off based on a control signal fromECU 100. The accuracy lamp is turned on when an estimation error ofcapacity retention Q is larger than a reference value. The accuracy lampis turned off when the estimation error of capacity retention Q is equalto or smaller than the reference value. Details of the accuracy lampwill be described later.

Warranty lamp 75 is turned on and off based on a control signal from ECU100. Warranty lamp 75 is turned off in a state of being ineligible forreceiving a warranty battery service (which will be described later) andturned on in a state of being eligible for receiving the warrantybattery service.

Referring again to FIG. 1, car navigator 80 includes a globalpositioning system (GPS) receiver that identifies a position of vehicle1 based on radio waves from an artificial satellite and a monitor with atouch panel that accepts an operation by a user and shows various typesof information (neither of which is shown).

Communication apparatus 90 can establish wired or wireless bidirectionalcommunication with a service tool 4. Communication apparatus 90 canestablish bidirectional communication also with a smartphone 5 of auser.

ECU 100 includes a central processing unit (CPU) 110, a memory 120, andan input and output port (not shown). ECU 100 may be divided into aplurality of ECUs for each function. Memory 120 includes a read onlymemory (ROM) and a random access memory (RAM), and stores a programexecuted by ECU 100 and a map used for various types of control. CPU 110develops a program stored in the ROM on the RAM and executes theprogram. CPU 110 outputs a control signal based on a signal from eachsensor and a map stored in memory 120 and controls each component to setvehicle 1 to a desired state.

Examples of primary control by ECU 100 in the present embodiment include“calculation processing” for calculating an SOC, a full charge capacity,and a capacity retention of battery 50 and “representation processing”for showing the calculated capacity retention on instrument panel 70.Calculation processing and representation processing will be describedin detail later.

Service tool 4 is a dedicated terminal installed in a dealer, a servicegarage, or the like, and diagnoses whether or not vehicle 1 is in anabnormal condition (including a state of battery 50). More specifically,service tool 4 includes a communication unit 401, a display 402, anoperation console 403, and a control unit 404. Control unit 404diagnoses whether or not vehicle 1 is in an abnormal condition byestablishing necessary communication with vehicle 1 throughcommunication unit 401 in accordance with an operation onto operationconsole 403 by a serviceperson, and has display 402 show a result ofdiagnosis.

Smartphone 5 includes a communication module 501, a touch panel display502, and a control unit 503. Control unit 503 can have touch paneldisplay 502 show various types of information on vehicle 1 bycommunicating with vehicle 1 through communication module 501 or canaccept an operation by a user onto touch panel display 502.

Instrument panel 70 corresponds to an exemplary “display apparatus”according to the present disclosure. ECU 100 corresponds to an exemplary“controller” according to the present disclosure. The “displayapparatus” according to the present disclosure is not limited toinstrument panel 70, and it may be car navigator 80 or a displayapparatus provided separately in vehicle 1.

Warranty of Battery

Vehicle 1 according to the present embodiment configured as above iscovered by a warranty (a battery warranty) offered by a manufacturer forreplacement of battery 50. A secondary battery has been known todeteriorate and lower in full charge capacity as it is used and timeelapses. In other words, as the secondary battery is used and timeelapses, the capacity retention lowers. When battery 50 deteriorates andthe capacity retention lowers (the full charge capacity lowers), amaximum EV driving range is shorter. When the EV driving range isshorter, the vehicle cannot travel over a long distance without externalcharging and convenience of a user is significantly impaired.

Therefore, the battery is covered by a warranty, for example, such thatbattery 50 is replaced by a manufacturer through a dealer or the likewhen deterioration of battery 50 progresses and capacity retention Q isequal to or lower than a threshold value. Contents of the batterywarranty are not limited to replacement of battery 50, and for example,battery 50 of which deterioration has progressed may be refreshed.Refresh processing for battery 50 may be, for example, such processing,for recovering the capacity of battery 50 by discharging battery 50until an SOC of battery 50 attains to a reference SOC and maintainingthe SOC of battery 50 at an SOC not higher than the reference SOC for acertain period of time. Alternatively, refresh processing for battery 50may be, for example, such processing for recovering the capacity ofbattery 50 by replacing a part of battery 50.

The threshold value is set, for example, to a value at which replacementof battery 50 is recommended, from a point of view of the EV drivingrange (for example, the EV driving range when battery 50 is fullycharged). Alternatively, the threshold value may be set, for example, toa value at which refresh processing for battery 50 is recommended from apoint of view of the EV driving range. The threshold value according tothe present embodiment is set to a capacity retention of 30%. Thethreshold value is not limited to the capacity retention of 30% and maybe set, for example, to a value higher or lower than the capacityretention of 30%.

The threshold value is not limited to a threshold value set for capacityretention Q. For example, the threshold value may be set for full chargecapacity C of battery 50. Since full charge capacity C is in proportionto capacity retention Q (see the expression (1) above), the thresholdvalue may be set for full charge capacity C, and the battery may beeligible for receiving a warranty battery service when the full chargecapacity is equal to or lower than the threshold value.

In order to be eligible for receiving the warranty battery service,however, a warranty condition to be eligible for receiving the warrantyservice should be satisfied. The warranty condition is satisfied, forexample, when both of (i) a condition that a period of ten years (whichis also referred to as a “warranty period” below) since start of use ofthe secondary battery has not elapsed and (ii) a condition that there isno excess over one hundred and fifty thousand miles of travel distance(which is also referred to as a “warranty distance” below) aresatisfied. In other words, when capacity retention Q of battery 50 isequal to or lower than the threshold value by the time of lapse of thewarranty period and by the time the vehicle travels the warrantydistance, the battery is eligible for receiving the warranty batteryservice. When the warranty period has elapsed or there is an excess overthe warranty distance, the battery is not eligible for receiving thewarranty battery service even though capacity retention Q of battery 50is equal to or lower than the threshold value.

The warranty period refers to a period for which capacity retention Q ofbattery 50 higher than the threshold value is guaranteed, and it isderived, for example, from statistics and/or specifications of battery50. Count of the warranty period starts, for example, on a day of newvehicle registration of vehicle 1. In other words, the warranty periodrefers to a period of ten years from the day of new vehicle registrationof vehicle 1. Alternatively, count of the warranty period may start, forexample, on the day of manufacturing of battery 50 or the day ofmanufacturing of vehicle 1. The warranty period is not limited to tenyears from start of use of the secondary battery, and the warrantyperiod may be shorter or longer than ten years from start of use of thesecondary battery.

The warranty distance refers to a distance up to which capacityretention Q of battery 50 higher than the threshold value is guaranteed,and it is derived, for example, from statistics and/or specifications ofbattery 50. The warranty distance is not limited to one hundred andfifty thousand miles, but may be shorter or longer than one hundred andfifty thousand miles.

In summary, the battery is eligible for receiving the warranty batteryservice “when the warranty condition is satisfied and capacity retentionQ is equal to or lower than the threshold value.” “When the warrantycondition is satisfied and capacity retention Q is higher than thethreshold value” or “when the warranty condition is not satisfied,” thebattery is not eligible for receiving, the warranty battery service.

In a general electric appliance including a secondary battery as amotive power source (for example, a smartphone familiar to a largenumber of users), an SOC as an indicator that indicates remaining powerof the secondary battery is always shown. On the other hand, thecapacity retention (or the full charge capacity) is not always shown inmany electric appliances. Therefore, a large number of users are notfamiliar with the capacity retention (full charge capacity).Accordingly, even though capacity retention Q is shown, for example, oninstrument panel 70, the user may not be able to intuitively recognizein which condition of shown full charge capacity Q the battery iseligible for receiving the warranty battery service.

Vehicle 1 according to the present embodiment notifies that the batteryis eligible for receiving the warranty battery service whendeterioration of battery 50 progresses and the battery is now eligiblefor receiving the warranty battery service. Specifically, when thewarranty condition is satisfied and capacity retention Q is equal to orlower than the threshold value, vehicle 1 according to the presentembodiment varies a manner of representation of capacity retention Qshown on multi-information display 74 of instrument panel 70. Withvariation in manner of representation of capacity retention Q, the usercan intuitively recognize eligibility for receiving the warranty batteryservice, that is, battery 50 can be replaced (or battery 50 can berefreshed).

Alternatively, when the warranty condition is satisfied and capacityretention Q is equal to or lower than the threshold value, a warning maybe shown on instrument panel 70. Specifically, warranty lamp 75 may beturned on when the warranty condition is satisfied and capacityretention Q is equal to or lower than the threshold value. With turn-onof warranty lamp 75 as well, the user can intuitively recognizeeligibility for receiving the warranty battery service. Instead ofwarranty lamp 75, a character may be shown, for example, onmulti-information display 74.

When the warranty condition is satisfied and capacity retention Q isequal to or lower than the threshold value, a manner of representationof capacity retention Q shown on multi-information display 74 ofinstrument panel 70 may be varied and additionally warranty lamp 75 maybe turned on. Thus, the user can more intuitively recognize eligibilityfor receiving the warranty battery service.

Variation in manner of representation of capacity retention Q andwarranty lamp 75 will be described with reference to FIGS. 3 and 4. FIG.4 is a diagram showing an example where capacity retention Q is shown onmulti-information display 74. FIG. 4 shows capacity retention Q shown onmulti-information display 74 when the warranty condition is satisfiedand capacity retention Q is equal to or lower than the threshold value.FIG. 3 shows capacity retention Q shown on multi-information display 74when the warranty condition is satisfied and capacity retention Q ishigher than the threshold value. As described above, the threshold valueaccording to the present embodiment is set to the capacity retention of30%. Namely, when capacity retention Q of battery 50 is equal to orlower than 30% while the warranty condition is satisfied, the battery iseligible for receiving the warranty battery service.

Referring to FIGS. 3 and 4, capacity retention Q is shown in firstdisplay section 76 of multi-information display 74 by turn-on ofsegments corresponding in number to capacity retention Q as describedabove. For example, in the example in FIG. 3 where capacity retention Qis 80%, segments 760 to 767 are turned on and segments 768 and 769 areturned off.

So long as the warranty condition is satisfied, colors of illuminationof segments are different between capacity retention Q of battery 50being higher than the threshold value and capacity retention Q beingequal to or lower than the threshold value. In other words, whencapacity retention Q is equal to or lower than the threshold value whilethe warranty condition is satisfied, the color of illumination ofsegments is varied.

By way of example, when capacity retention Q is 80% (FIG. 3), the colorof illumination of segments is set to blue. When capacity retention Q is30% (FIG. 4), the color of illumination of segments is set to red.Setting of the color of illumination of segments is merely by way ofexample. The color of illumination of segments can be set asappropriate.

When deterioration of battery 50 progresses and capacity retention Q isequal to or lower than the threshold value (when the battery is eligiblefor receiving the warranty battery service), the color of illuminationof segments is varied from blue to red. The user can thus visuallyrecognize variation in representation. Therefore, the user canintuitively recognize eligibility for receiving the warranty batteryservice.

Alternatively, when deterioration of battery 50 progresses and capacityretention Q is equal to or lower than the threshold value, warranty lamp75 may be turned on. FIG. 3 shows an example where warranty lamp 75 isturned off and FIG. 4 shows an example where warranty lamp 75 is turnedon. As warranty lamp 75 is turned on when the battery is eligible forreceiving the warranty battery service, the user can visually recognizevariation in representation. Therefore, the user can intuitivelyrecognize eligibility for receiving the warranty battery service.

When the battery is eligible for receiving the warranty battery service,the color of illumination of segments may be varied and warranty lamp 75may be turned on. Based on such combination, the user can moreintuitively recognize eligibility for receiving the warranty batteryservice.

When the warranty condition is not satisfied, the battery is noteligible for receiving the warranty battery service even though capacityretention Q is equal to or lower than the threshold value. If anotification that capacity retention Q is equal to or lower than thethreshold value is given even in such a case, the user may erroneouslyrecognize eligibility for receiving the warranty service or may feelbothered by the notification given in spite of ineligibility forreceiving the warranty service. Then, when the warranty condition is notsatisfied, a notification that capacity retention Q is equal to or lowerthan the threshold value is not given even though capacity retention Qis equal to or lower than the threshold value. Thus, erroneousrecognition by the user caused by the notification or the user beingbothered by the notification can be suppressed.

Environments (for example, temperature TB of battery 50, though detailswill be described later) where capacity retention Q is estimated arevarious, and the capacity retention is not necessarily always estimatedin a stable environment. Therefore, there are various factors that mayvary an estimated value of capacity retention Q. When an estimationerror of capacity retention Q is large, for example, there is a concernas below. Capacity retention Q (first display section 76 and seconddisplay section 77) shown on multi-information display 74 at each timingof estimation of capacity retention Q may greatly fluctuate, which maymake a user feel strange. Alternatively, although capacity retention Qshown on multi-information display 74 is equal to or lower than thethreshold value, at next timing of estimation of capacity retention Q,capacity retention Q may be higher than the threshold value.Alternatively, an example is also possible in which, since capacityretention Q shown on multi-information display 74 is equal to or lowerthan the threshold value, a user brings his/her vehicle 1 immediately toa dealer, but when capacity retention Q is estimated by service tool 4in a stable environment, capacity retention Q is higher than thethreshold value.

Then, when an estimation error of capacity retention Q is large, thirddisplay section 78 is turned on to give a notification to a user. Asthird display section 78 is turned on, the user can recognize thataccuracy of currently shown capacity retention Q may be low andrepresentation may not be accurate. Thus, even though capacity retentionQ shown at each estimation timing fluctuates, strange feeling felt bythe user can be lessened as compared with an example where the user isunaware of low accuracy of shown capacity retention Q. Calculation of anestimation error of capacity retention Q will be described withreference to FIG. 5.

Calculation Processing and Representation Processing

<<Calculation Processing>>

FIG. 5 is a flowchart showing calculation processing in the presentembodiment. This flowchart is performed by ECU 100, for example, when aprescribed condition is satisfied (for example, when a defined timeperiod has elapsed since previous estimation of capacity retention Q).Though each step (the step being abbreviated as “S” below) included inthis flowchart and FIG. 9 which will be described later is basicallyperformed by software processing by ECU 100, it may be performed bydedicated hardware (electric circuitry) fabricated in ECU 100.

Referring to FIG. 5, processing from S101 to S107 is processing forcalculating a capacity retention of battery 50 and an estimation errorthereof (calculation processing).

In S101, ECU 100 obtains a left-stand time period Δt of battery 50.Left-stand time period Δt (which is also called a stand-by time period)means a time period for which battery 50 was left stand without beingcharged or discharging before start of the flow (that is, a time periodelapsed since previous charging and discharging of battery 50).

In S102, ECU 100 calculates an. SOC of battery 50. This SOC is referredto as a “start SOC” and denoted also as an SOC1. A known method offinding an SOC based on an OCV by referring to an OCV-SOC curve ofbattery 50 obtained in advance can be employed as a method of estimatingthe start SOC.

In S103, ECU 100 calculates again the SOC of battery 50. This SOC isreferred to as an “end SOC” and denoted also as an SOC2.

In S104, ECU 100 calculates an amount of charging, and discharging powerΔAh in charging and discharging of battery 50 during a period fromestimation of the start SOC until estimation of the end SOC. Amount ofpower ΔAh can be calculated by integrating a value of a current thatflows in battery 50, with the use of the current sensor included inmonitoring unit 51. A unit for amount of charging and discharging powerΔAh is not limited to ampere-hour but may be watt-hour.

In S105, ECU 100 calculates full charge capacity C of battery 50.Specifically, ECU 100 can calculate full charge capacity C of battery 50in accordance with an expression (2) below, based on the SOC1 and theSOC2 representing results in two calculations of the SOC and amount ofcharging and discharging power ΔAh.

C=ΔAh/|SOC1−SOC2|×100  (2)

In S106, ECU 100 estimates capacity retention Q of battery 50. Capacityretention Q of battery 50 is calculated by dividing full charge capacityC by an initial value C0 of the full charge capacity of battery 50 asdescribed with reference to the expression (1).

In S107, ECU 100 calculates an error ε of capacity retention Q estimatedin S106 (a capacity estimation error).

FIG. 6 is a diagram for illustrating an exemplary method of calculatingcapacity estimation error ε of battery 50. In FIG. 6, the abscissarepresents the start SOC and the ordinate represents capacity estimationerror ε.

With conditions defined by combination (Δt, SOC1, and TB) of left-standtime period Δt, the start SOC (SOC 1), and battery temperature TB beingvariously changed, full charge capacity C under each condition ismeasured. FIG. 6 shows an error in calculation of full charge capacity C(=capacity estimation error ε) when left-stand time period Δt is variedbetween two options (one minute or sixty minutes) and the start SOC isvariously changed within a range from 0% to 85% at one batterytemperature TB (30° C. in this example). By measuring full chargecapacity C of a plurality of batteries placed under the same condition,an error in calculation of full charge capacity C under that conditioncan be calculated. Since full charge capacity C and capacity retention Qare in proportion to each other (see the expression (1) above), theerror in calculation of full charge capacity C matches with capacityestimation error ε. Therefore, capacity estimation error ε under eachcondition can be found by measurement above.

As shown in FIG. 6, when the start SOC is included in an intermediateSOC region (a region of the SOC from approximately 30% to 70% in theexample shown in FIG. 6), capacity estimation error ε is larger than inan example where the start SOC is included in a low SOC region (a regionof the SOC lower than 30%). This is because of a typical shape of theOCV-SOC curve, that is, such a shape that the inclination of the curveis steep in the low SOC region whereas it is flat in the intermediateSOC region. Because of this shape of the curve, in the intermediate SOCregion as compared with the low SOC region, a slight error in OCV leadsto a large SOC error. Then, an error in calculation of full chargecapacity C is larger, and consequently capacity estimation errors islarger (see the expressions (1) and (2) above).

In general, the battery is polarized by charging and discharging.Polarization produced in battery 50 causes deviation of voltage VBrepresenting a voltage across terminals (a closed circuit voltage (CCV))of battery 50 from the OCV and generation of the OCV error. Polarizationremains without being canceled until lapse of a certain time period(approximately several ten minutes) after end of charging anddischarging of battery 50. Therefore, when left-stand time period Δt ofbattery 50 is short (one minute in the example shown in FIG. 6),accuracy of the OCV is lower than in an example where left-stand timeperiod Δt is long (sixty minutes). Then, an error in SOC is generatedand an error in calculation of full charge capacity C is larger. Namely,capacity estimation error ε is larger.

Though not shown, under such a condition that both of the start SOC ofbattery 50 and left-stand time period Δt are equal, polarization is lesslikely to be canceled as battery temperature TB is lower. Therefore, asbattery temperature. TB is lower, the error in OCV is larger and hencecapacity estimation error ε is larger.

Capacity estimation error c of battery 50 is thus dependent on the startSOC of battery 50, left-stand time period Δt, and battery temperatureTB. Therefore, capacity estimation error ε can be calculated based onthese three parameters. In the present embodiment, a map MP forcalculation of capacity estimation error ε is prepared. Though FIG. 6shows capacity estimation error ε with combination (Δt and SOC1) ofleft-stand time period Δt and the start SOC (SOC1) at specific batterytemperature TB being varied, map MP can be prepared by calculatingcapacity estimation error ε with combination of the three parameters(Δt, SOC1, and TB) being varied.

FIG. 7 is a conceptual diagram showing map MP for calculating capacityestimation error ε of battery 50. Referring to FIG. 7, athree-dimensional map MP for calculating capacity estimation error εbased on left-stand time period Δt of battery 50, the start SOC, andbattery temperature TB is stored in a memory (not shown) of ECU 100. Byreferring to map MP, ECU 100 can calculate capacity estimation error εbased on the three parameters.

For example, when battery 50 is not charged or discharged due to vehicle1 remaining stopped, capacity retention Q (and capacity estimation errorε) cannot be calculated by performing calculation processing. In thiscase, an estimated value of capacity retention Q obtained in previouscalculation processing and a calculated value of capacity estimationerror ε can be used as results of processing in S106 and S107. When along time period (for example, several months) have elapsed sinceprevious calculation processing, however, deterioration of battery 50may progress and capacity retention Q and capacity estimation error εmay vary also during that period. In such a case, current capacityretention Q and capacity estimation error ε are calculated as below.

FIG. 8 is a diagram for illustrating a method of calculating capacityretention Q and capacity estimation error ε of battery 50. In FIG. 8,the abscissa represents elapsed time and the ordinate representscapacity retention Q of battery 50.

As shown in FIG. 8, as the time elapsed since previous calculationprocessing is longer, capacity retention Q is lower and an error ofcapacity retention Q (capacity estimation error ε) is larger. Therefore,correlation of time elapsed since previous calculation processing withcapacity retention Q and capacity estimation error ε is found throughexperiments in advance, and a map (not shown) based on results of theexperiments is prepared. By thus referring to the map, capacityretention Q and capacity estimation error ε can be calculated based onthe time elapsed since previous calculation processing.

<<Representation Processing>>

FIG. 9 is a flowchart showing representation processing in the presentembodiment. This flowchart is performed by ECU 100 following thecalculation processing.

In S201, ECU 100 determines whether or not the warranty condition issatisfied. Specifically, ECU 100 determines whether or not the warrantyperiod has elapsed and the travel distance of vehicle 1 has exceeded thewarranty distance. When the warranty condition is satisfied (YES inS201), the process proceeds to S202. When the warranty condition is notsatisfied (NO in S201), the process proceeds to S203.

In S202, ECU 100 determines whether or not capacity retention Qestimated in calculation processing is equal to or lower than thethreshold value. When capacity retention Q is equal to or lower than thethreshold value (YES in S202), ECU 100 allows the process to proceed toS204. When capacity retention Q is higher than the threshold value (NOin S202), ECU 100 allows the process to proceed to S203.

In S203, ECU 100 sets a manner of representation of segments to a firstmanner and turns on segments in accordance with capacity retention Q.Specifically, ECU 100 sets the color of illumination of segments, forexample, to blue, and turns on segments in accordance with capacityretention Q. Then, ECU 100 performs S203 and thereafter quits theprocess.

In S204, ECU 100 sets the manner of representation of the segments to asecond manner and turns on segments in accordance with capacityretention Q. Specifically, ECU 100 sets the color of illumination ofsegments, for example, to red, and turns on segments in accordance withcapacity retention Q. When the warranty condition is satisfied andcapacity retention Q is equal to or lower than the threshold value, byvarying the manner of representation of the segments (varying the colorof illumination), the user is allowed to intuitively recognizeeligibility for receiving the warranty battery service. In S204, insteadof or in addition to setting of the manner of representation of thesegments to the second manner, ECU 100 may turn on warranty lamp 75. Bydoing so as well, the user can intuitively recognize eligibility forreceiving the warranty battery service.

In S205 that follows, ECU 100 determines whether or not an error ofcapacity retention Q (capacity estimation error ε) estimated incalculation processing has exceeded the reference value. When capacityestimation error ε has exceeded the reference value (YES in S205), ECU100 allows the process to proceed to S206. When capacity estimationerror ε is equal to or lower than the reference value (NO in S205), ECU100 allows the process to proceed to S207.

In S206, ECU 100 turns on the accuracy lamp in third display section 78.Thus, the user can recognize low accuracy in estimation of capacityretention Q shown on multi-information display 74.

In S207, ECU 100 turns off the accuracy lamp in third display section78. Thus, the user can recognize high accuracy in estimation of capacityretention Q shown on multi-information display 74.

As set forth above, in the present embodiment, when deterioration ofbattery 50 progresses and the battery is now eligible for receiving thewarranty battery service, a notification that the battery is eligiblefor receiving the warranty battery service is given. Specifically, whenthe warranty condition is satisfied and capacity retention Q is equal toor lower than the threshold value, a notification that capacityretention Q is equal to or lower than the threshold value is given. Bygiving the notification that capacity retention Q is equal to or lowerthan the threshold value, even though the user is unfamiliar withcapacity retention Q, the user can intuitively recognize eligibility forreceiving the warranty battery service.

More specifically, when capacity retention Q is higher than thethreshold value (for example, the capacity retention of 30%), capacityretention Q is shown in the first manner (the color of illumination ofsegments being set, for example, to blue). When capacity retention Q isequal to or lower than the threshold value while the warranty condition,is satisfied, capacity retention Q is shown in the second manner (thecolor of illumination of segments being set, for example, to red). Thus,as the manner of representation of capacity retention Q is varied fromthe first manner to the second manner when the battery has becomeeligible for receiving the warranty battery service, the user canintuitively recognize eligibility for receiving the warranty batteryservice even though the user is unfamiliar with capacity retention Q.

When the warranty condition is not satisfied even though capacityretention Q is equal to or lower than the threshold value, capacityretention Q is shown in the first manner. If a notification thatcapacity retention Q is equal to or lower than the threshold value isgiven even when the warranty condition is no longer satisfied, the usermay erroneously recognize eligibility for receiving the warranty batteryservice or may feel bothered by the notification given in spite ofineligibility for receiving the warranty battery service. When thewarranty condition is not satisfied, capacity retention Q is shown inthe first manner so that erroneous recognition by the user caused by thenotification or the user being bothered by the notification can besuppressed.

Ease in control may be prioritized. Specifically, regardless of whetheror not the warranty condition is satisfied, capacity retention Q may beshown in the first manner when capacity retention Q is higher than thethreshold value, and capacity retention Q may be shown in the secondmanner when capacity retention Q is equal to or lower than the thresholdvalue.

When deterioration of battery 50 progresses and the battery is noweligible for receiving the warranty battery service, a notificationabout eligibility for receiving the warranty battery service may begiven by turning on warranty lamp 75. With turn-on of warranty lamp 75,even though the user is unfamiliar with capacity retention Q, the usercan intuitively recognize eligibility for receiving the warranty batteryservice.

When deterioration of battery 50 progresses and the battery is noweligible for receiving the warranty battery service, capacity retentionQ may be shown in the second manner and warranty lamp 75 may be turnedon. Thus, even though the user is unfamiliar with capacity retention Q,the user can more intuitively recognize eligibility for receiving thewarranty battery service.

When an error of capacity retention Q (capacity estimation error ε) islarger than the reference value, the accuracy lamp in third displaysection 78 is turned on. The user can thus recognize low accuracy inestimation of shown capacity retention Q.

Though an example in which capacity retention Q is shown in vehicle 1(instrument panel 70 and/or car navigator 80) is described above,capacity retention Q may be shown, for example, on service tool 4. Inthis case, display 402 of service tool 4 corresponds to an exemplary“display apparatus” according to the present disclosure. Control unit404 of service tool 4 corresponds to an exemplary “controller” accordingto the present disclosure. Furthermore, capacity retention Q may beshown on smartphone 5. In this case, touch panel display 502 ofsmartphone 5 corresponds to an exemplary “display apparatus” accordingto the present disclosure. Control unit 503 of smartphone 5 correspondsto an exemplary “controller” according to the present disclosure.

Though an example in which capacity retention Q can selectively be shownon multi-information display 74 is described in the present embodiment,capacity retention Q may always be shown on instrument panel 70separately from multi-information display 74. In this case, for example,when capacity retention Q is shown with segments, the segments mayphysically be provided or virtually provided as in the embodiment.

In the present embodiment, the threshold value is set for determiningeligibility for receiving the warranty battery service. The thresholdvalue, however, can also be set from a different point of view. Forexample, the threshold value may be set for determining whether or notbattery 50 is reusable. Namely, the threshold value may be set fordetermining whether or not battery 50 is worth a secondhand battery. Bythus setting the threshold value, the user can visually recognizewhether or not battery 50 is reusable at the current time point.

[First Modification]

In the embodiment, when deterioration of battery 50 progresses and thebattery is now eligible for receiving the warranty battery service, anotification about eligibility for receiving the warranty batteryservice is given by varying the color of illumination of segments. Anotification about eligibility for receiving the warranty batteryservice, however, may be given in another manner.

FIG. 10 is a diagram showing an example where capacity retention Q isshown on multi-information display 74 in a first modification. In thefirst modification, regardless of eligibility for receiving the warrantybattery service, segments 763 to 769 corresponding to capacity retentionQ higher than the threshold value and segments 760 to 762 correspondingto capacity retention Q equal to or lower than the threshold value areturned on in colors different from each other.

FIG. 10 shows exemplary representation when capacity retention Q is 80%.For example, segments 768 to 769 are turned off, segments 763 to 767 areturned on in blue, and segments 760 to 762 are turned on in red. Forexample, when capacity retention Q is equal to or lower than 30%,segments 763 to 769 are turned off and segments 760 to 762 are turnedon. In this case, as the segments that are turned on are in a red coloralone, the user can visually recognize change from the state thatsegments were turned on also in blue in addition to red. Namely, theuser can recognize variation in manner of representation of capacityretention. With variation in manner of representation of capacityretention Q, the user can intuitively recognize eligibility forreceiving the warranty battery service.

[Second Modification]

In a second modification, yet another example of a notification abouteligibility for receiving the warranty battery service will bedescribed. FIG. 11 is a diagram showing an example where capacityretention Q is shown on multi-information display 74 in the secondmodification. In the second modification, a color of illumination ofsegments in first display section 76 are different in density.Specifically, segments 760 to 769 are set such that the color ofillumination thereof becomes lighter in this order. Specifically, amongsegments 760 to 769, segment 760 is highest and segment 769 is lowest indensity of the color of illumination.

FIG. 11 shows exemplary representation when capacity retention Q is 50%.When transition from the state shown in FIG. 11 to capacity retention Q,for example, of 30% is made, segments 763 to 769 are turned off andsegments 760 to 762 are turned on. In this case, only segments in arelatively dense illumination color are turned on so that the user canvisually recognize variation in manner of representation. With variationin manner of representation of capacity retention Q, the user canintuitively recognize eligibility for receiving the warranty batteryservice.

[Third Modification]

In a third modification, yet another example of a notification abouteligibility for receiving the warranty battery service will bedescribed. FIG. 12 is a diagram showing an example where capacityretention Q is shown on multi-information display 74 in the thirdmodification. A mark B that indicates the threshold value in addition tosegments 760 to 769 is further shown in first display section 76according to the third modification.

With representation of mark B indicating the threshold value, whensegments that are turned on are lower than mark B, the user canrecognize eligibility for receiving the warranty battery service. In theexample shown in FIG. 12, with representation of mark B, when transitionof segment 763 from on to off is made, that is, when segment 762 is theuppermost segment that is turned on, the user recognizes that thesegment that is turned on is lower than mark B. With representation ofmark B indicating the threshold value in addition to segments 760 to769, the user can intuitively recognize eligibility for receiving thewarranty battery service.

[Fourth Modification]

A warranty condition may be shown on multi-information display 74. Awarranty condition may be shown together with capacity retention Q, ormay selectively be shown on multi-information display 74 like a drivingrange, an average vehicle speed, and a state of regeneration/powerrunning of battery 50. In a fourth modification, an example where thewarranty condition is shown together with capacity retention Q will bedescribed.

FIG. 13 is a diagram showing an example where capacity retention Q and awarranty condition are shown on multi-information display 74.Multi-information display 74 further includes a fourth display section79 in addition to first display section 76, second display section 77,and third display section 78.

A warranty condition is shown in fourth display section 79.Specifically, a warranty period and a warranty distance are shown infourth display section 79. FIG. 13 shows ten years as the warrantyperiod and one hundred and fifty thousand miles as the warrantydistance.

Representation of the warranty condition is not limited torepresentation of the warranty condition itself (the warranty period andthe warranty distance themselves). For example, days that remain at thecurrent time point may be shown as the warranty period. The last day ofthe warranty period (an expiration date of the warranty period) may beshown as the warranty period. A distance that remains at the currenttime point may be shown as the warranty distance. With representation ofthe warranty condition, the user can recognize the warranty condition.Therefore, expiration of the warranty period or excess of the traveldistance of vehicle 1 over the prescribed distance without receiving thewarranty service in spite of eligibility for receiving the warrantybattery service can be suppressed. The warranty condition (including themodification above) shown in fourth display section 79 corresponds to anexemplary “second indicator” according to the present disclosure.

When the warranty condition is no longer satisfied, that is, thewarranty period has expired or the travel distance of vehicle 1 hasexceeded the warranty distance, a notification that the warrantycondition is no longer satisfied may be given.

For example, by causing the warranty condition shown in fourth displaysection 79 to blink or varying a color of representation thereof, anotification that the warranty condition is no longer satisfied isgiven. For example, when the warranty period has expired, the warrantyperiod shown in fourth display section 79 is caused to blink. The usercan thus recognize that the warranty condition is no longer satisfieddue to expiration of the warranty period. For example, when the traveldistance of vehicle 1 exceeds the warranty distance, the warrantydistance shown in fourth display section 79 is caused to blink.

For example, a notification that the warranty condition is no longersatisfied may be given by showing a character indicating that thewarranty condition is no longer satisfied.

[Fifth Modification]

An example where segment representation of capacity retention Q isprovided in first display section 76 of multi-information display 74 isdescribed in the embodiment and the first to fourth modifications.Limitation to segment representation of capacity retention Q in firstdisplay section 76, however, is not intended. In a fifth modification,an example where capacity retention Q is shown in another manner infirst display section 76 will be described.

FIG. 14 is a diagram showing an example where capacity retention Q isshown on multi-information display 74 in another manner. Referring toFIG. 14, first display section 76 includes a scale M1 and a needle M2.First display section 76 shows capacity retention Q of battery 50 withscale M1 and needle M2. Capacity retention Q is pointed to by needle M2.A numeric value provided to scale M1 specifies a value pointed to byneedle M2 (that is, capacity retention Q pointed to by needle M2). Asshown in FIG. 14, needle M2 is shown to continuously move in a directionD1 and a direction D2.

FIG. 14 shows an example where capacity retention Q is 40%. In the fifthmodification, scale M1 corresponding to current capacity retention Q isshown to illuminate. Until capacity retention Q is equal to or lowerthan the threshold value, for example, scale M1 is shown to illuminatein blue. When capacity retention Q is equal to or lower than thethreshold value while the warranty condition is satisfied, the color ofillumination of scale M1 is changed to red. When battery 50 is noweligible for receiving the warranty service, the color of illuminationof scale M1 is varied. The user can thus visually recognize variation inrepresentation. Therefore, the user can intuitively recognizeeligibility for receiving the warranty battery service.

[Sixth Modification]

In the fifth modification, the color of illumination of scale M1 isvaried when the battery is now eligible for receiving the warrantybattery service. In a sixth modification, an example where a color ofillumination of needle M2 is varied when the battery is now eligible forreceiving the warranty battery service will be described.

FIG. 15 is a diagram showing another example where capacity retention Qis shown on multi-information display 74 in another manner. When thebattery is now eligible for receiving the warranty battery service, thecolor of illumination of needle M2 is varied. For example, when thebattery is now ineligible for receiving the warranty battery service,needle M2 may be turned on in blue, and when the battery is now eligiblefor receiving the warranty battery service, needle M2 may be turned onin red. When the battery is now eligible for receiving the warrantybattery service, the color of illumination of needle M2 is varied. Theuser can thus visually recognize variation in representation. Therefore,the user can intuitively recognize eligibility for receiving thewarranty battery service.

[Seventh Modification]

In the embodiment and the first to sixth modifications, the color ofillumination of segments, the color of illumination of scale M1, or thecolor of illumination of needle M2 is varied between a state ofineligibility for receiving the warranty battery service and a state ofeligibility for receiving the warranty battery service.

As described above, the state of ineligibility for receiving thewarranty battery service is that (1) the warranty condition is satisfiedand capacity retention Q is higher than the threshold value or (2) thewarranty condition is not satisfied. When (2) the warranty condition isnot satisfied, segments, scale M1, or needle M2 may be turned on in yetanother color.

In summary, in the case of (1) above, in the case of (2) above, and in acase of (3) where the warranty condition is satisfied and capacityretention Q is equal to or lower than the threshold value (the state ofeligibility for receiving the warranty battery service), segments, scaleM1, or needle M2 may be turned on in different colors. The user can thusrecognize in which state battery 50 is in.

The embodiment and the first to seventh, modifications may be carriedout with all or some of them being combined.

Though an embodiment of the present disclosure has been described, itshould be understood that the embodiment disclosed herein isillustrative and non-restrictive in every respect. The scope of thepresent disclosure is defined by the terms of the claims and is intendedto include any modifications within the scope and meaning equivalent tothe terms of the claims.

What is claimed is:
 1. A display system comprising: a display apparatusthat shows a first indicator relating to a full charge capacity of asecondary battery; and a controller that controls the display apparatus,wherein the controller controls the display apparatus to notify, when afull charge capacity of the secondary battery is equal to or lower thana threshold value, that the full charge capacity of the secondarybattery is equal to or lower than the threshold value.
 2. The displaysystem according, to claim 1, wherein the controller controls thedisplay apparatus to notify that the full charge capacity of thesecondary battery is equal to or lower than the threshold value byvarying a manner of representation of the first indicator.
 3. Thedisplay system according to claim 1, wherein the controller controls thedisplay apparatus to notify that the full charge capacity of thesecondary battery is equal to or lower than the threshold value byshowing a warning.
 4. The display system according to claim 1, whereinthe controller controls the display apparatus to notify, when anestimation error of the full charge capacity of the secondary batteryexceeds a reference value, that accuracy of the first indicator is low.5. The display system according to claim 1, wherein the displayapparatus shows a capacity retention in segment representation as thefirst indicator, the capacity retention representing a ratio of acurrent full charge capacity to an initial full charge capacity of thesecondary battery, and the controller controls the display apparatus toturn on segments corresponding, in number to the capacity retention, andcontrols the display apparatus to vary a color of at least one of thesegments when the full charge capacity of the secondary battery is equalto or lower than the threshold value.
 6. The display system according toclaim 1, wherein the controller controls the display apparatus to notifythat the full charge capacity of the secondary battery is equal to orlower than the threshold value when a warranty condition is satisfied,and controls the display apparatus not to notify that the full chargecapacity of the secondary battery is equal to or lower than thethreshold value when the warranty condition, is not satisfied.
 7. Thedisplay system according to claim 6, wherein the warranty condition issatisfied when a prescribed period has not elapsed since start of use ofthe secondary battery.
 8. The display system according to claim 6,wherein the warranty condition is satisfied when a travel distance of avehicle incorporating the secondary battery is shorter than a prescribeddistance.
 9. The display system according to claim 6, wherein thewarranty condition is satisfied when a prescribed period has not elapsedsince start of use of the secondary battery and when a travel distanceof a vehicle incorporating the secondary battery is shorter than aprescribed distance.
 10. The display system according to claim 1,wherein the controller controls the display apparatus to notify, when awarranty condition is not satisfied, that the warranty condition is notsatisfied.
 11. The display system according to claim 6, wherein thecontroller controls the display apparatus to notify, when the warrantycondition, is not satisfied, that the warranty condition is notsatisfied.
 12. The display system according to claim 1, wherein thecontroller controls the display apparatus to show a second indicatorrelating to a warranty condition.
 13. The display system according toclaim 6, wherein the controller controls the display apparatus to show asecond indicator relating to the warranty condition.
 14. A vehiclecomprising: the secondary battery; and the display system according toclaim
 1. 15. A method of showing, a state of a secondary battery byshowing a first indicator relating to a full charge capacity of thesecondary battery, the method comprising: obtaining a full chargecapacity of the secondary battery; and notifying, when the full chargecapacity of the secondary battery is equal to or lower than a thresholdvalue, that the full charge capacity of the secondary battery is equalto or lower than the threshold value.